Eur. Phys. J. D 21, 205-215 (2002)
https://doi.org/10.1140/epjd/e2002-00188-9

Storage of electromagnetic field energy in matter

Environmental and Water Resources Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel

Corresponding author: ^a zimmels@tx.technion.ac.il

Received: 6 June 2000
Revised: 26 March 2002
Published online: 24 September 2002

Abstract

The partitioning, uniqueness and form of field energy stored in matter, and its properties as a state function, is established. Consequently, the first and second laws apply to the nonfield and field parts of the internal energy as separate entities. This provides a bridge between thermodynamics and the classical theory of electromagnetism. Presentation of the temperature as the sum of nonfield and field contributions is used to establish field dependent barriers to temperature decrease toward the absolute zero, and the existence of field induced temperature jumps. These temperature jumps appear at the instant the field is switched on, or turned off. The partitioning of field and nonfield energies is illustrated for a specific case of an ideal gas, and the heat absorbed by the field is derived in terms of difference in adiabatic magnetization. Finally, the current, restrictive, form of electromagnetic field energy density is redefined with respect to the effect of field energy stored outside the system boundaries.